Low toxicity and long circulation time of polyampholyte-coated magnetic nanoparticles for blood pool contrast agents

Comprehensive Analysis of the Potential Toxicity of Magnetic Iron Oxide Nanoparticles for Medical Applications: Cellular Mechanisms and Systemic Effects

Owing to recent advancements in nanotechnology, magnetic iron oxide nanoparticles (MNPs), particularly magnetite (Fe3O4) and maghemite (γ-Fe2O3), are currently widely employed in the field of medicine. These MNPs, characterized by their large specific surface area, potential for diverse functionalization, and magnetic properties, have found application in various medical domains, including tumor imaging (MRI), radiolabelling, internal radiotherapy, hyperthermia, gene therapy, drug delivery, and theranostics. However, ensuring the non-toxicity of MNPs when employed in medical practices is paramount. Thus, ongoing research endeavors are essential to comprehensively understand and address potential toxicological implications associated with their usage. This review aims to present the latest research and findings on assessing the potential toxicity of magnetic nanoparticles. It meticulously delineates the primary mechanisms of MNP toxicity at the cellular level, encompassing oxidative stress, genotoxic effects, disruption of the cytoskeleton, cell membrane perturbation, alterations in the cell cycle, dysregulation of gene expression, inflammatory response, disturbance in ion homeostasis, and interference with cell migration and mobility. Furthermore, the review expounds upon the potential impact of MNPs on various organs and systems, including the brain and nervous system, heart and circulatory system, liver, spleen, lymph nodes, skin, urinary, and reproductive systems.

Enhancing Drug Delivery Efficacy Through Bilayer Coating of Zirconium-Based Metal-Organic Frameworks: Sustained Release and Improved Chemical Stability and Cellular Uptake for Cancer Therapy

The development of nanoparticle (NP)-based drug carriers has presented an exciting opportunity to address challenges in oncology. Among the 100,000 available possibilities, zirconium-based metal-organic frameworks (MOFs) have emerged as promising candidates in biomedical applications. Zr-MOFs can be easily synthesized as small-size NPs compatible with intravenous injection, whereas the ease of decorating their external surfaces with functional groups allows for targeted treatment. Despite these benefits, Zr-MOFs suffer degradation and aggregation in real, in vivo conditions, whereas the loaded drugs will suffer the burst effect-i.e., the fast release of drugs in less than 48 h. To tackle these issues, we developed a simple but effective bilayer coating strategy in a generic, two-step process. In this work, bilayer-coated MOF NU-901 remained well dispersed in biologically relevant fluids such as buffers and cell growth media. Additionally, the coating enhances the long-term stability of drug-loaded MOFs in water by simultaneously preventing sustained leakage of the drug and aggregation of the MOF particles. We evaluated our materials for the encapsulation and transport of pemetrexed, the standard-of-care chemotherapy in mesothelioma. The bilayer coating allowed for a slowed release of pemetrexed over 7 days, superior to the typical 48 h release found in bare MOFs. This slow release and the related performance were studied in vitro using both A549 lung cancer and 3T mesothelioma cells. Using high-resolution microscopy, we found the successful uptake of bilayer-coated MOFs by the cells with an accumulation in the lysosomes. The pemetrex-loaded NU-901 was indeed cytotoxic to 3T and A549 cancer cells. Finally, we demonstrated the general approach by extending the coating strategy using two additional lipids and four surfactants. This research highlights how a simple yet effective bilayer coating provides new insights into the design of promising MOF-based drug delivery systems.

A review: hemocompatibility of magnetic nanoparticles and their regenerative medicine, cancer therapy, drug delivery, and bioimaging applications

Nanoparticles have demonstrated noteworthy advancements in the management of various complex medical conditions, particularly cancer. In any case, these particles still harbor the potential to improve medicate conveyance to challenging, hard-to-reach loci. The interactions that occur between nanoparticles and red blood cells during their journey throughout the human body, despite exposure to blood, are still not fully understood. Assessment of the ability of nanoparticles to integrate with blood, characterized as nanoparticle compatibility, has been consistently overlooked and undervalued in its import. This review article investigates the effect of nanoparticles on red blood cells, while examining the compatibility of nanoparticles through the angle of hemolysis. This article discusses the main roles of erythrocytes and also provides an informed interpretation of several mechanisms involved in the interaction of nanoparticles and erythrocytes. Throughout the review, significant emphasis is attributed to the investigation of hemocompatibility studies concerning newly designed nanoparticles to promote their successful translation into clinical application. This review article examines the compatibility of magnetic nanoparticles in various fields, including regenerative medicine, cancer therapy, bioimaging, and drug delivery. Our results show that the chemical composition of the nanoparticle surface is a determining factor in hemocompatibility performance and interaction with blood cells. The surface properties of nanoparticles, namely surface charge, geometry, porosity, and surface functionalities of polymers or specific functional groups, represent key determinants of hemocompatibility.

Pharmacokinetics of magnetic iron oxide nanoparticles for medical applications

Magnetic iron oxide nanoparticles (MNPs) have been under intense investigation for at least the last five decades as they show enormous potential for many biomedical applications, such as biomolecule separation, MRI imaging and hyperthermia. Moreover, a large area of research on these nanostructures is concerned with their use as carriers of drugs, nucleic acids, peptides and other biologically active compounds, often leading to the development of targeted therapies. The uniqueness of MNPs is due to their nanometric size and unique magnetic properties. In addition, iron ions, which, along with oxygen, are a part of the MNPs, belong to the trace elements in the body. Therefore, after digesting MNPs in lysosomes, iron ions are incorporated into the natural circulation of this element in the body, which reduces the risk of excessive storage of nanoparticles. Still, one of the key issues for the therapeutic applications of magnetic nanoparticles is their pharmacokinetics which is reflected in the circulation time of MNPs in the bloodstream. These characteristics depend on many factors, such as the size and charge of MNPs, the nature of the polymers and any molecules attached to their surface, and other. Since the pharmacokinetics depends on the resultant of the physicochemical properties of nanoparticles, research should be carried out individually for all the nanostructures designed. Almost every year there are new reports on the results of studies on the pharmacokinetics of specific magnetic nanoparticles, thus it is very important to follow the achievements on this matter. This paper reviews the latest findings in this field. The mechanism of action of the mononuclear phagocytic system and the half-lives of a wide range of nanostructures are presented. Moreover, factors affecting clearance such as hydrodynamic and core size, core morphology and coatings molecules, surface charge and technical aspects have been described.

Engineering chitosan nano-cocktail containing iron oxide and ceria: A two-in-one approach for treatment of inflammatory diseases and tracking of material delivery

In this study, modular two-in-one nano-cocktails were synthesised to provide treatment of inflammatory diseases and also enable tracking of their delivery to the disease sites. Chitosan nano-cocktails loaded with treatment module (cerium oxide nanoparticles) and imaging module (iron oxide nanoparticles) were synthesised by electrostatic self-assembly (Chit-IOCO) and ionic gelation method (Chit-TPP-IOCO), respectively. Their MRI capability, anti-inflammatory and anti-fibrosis ability were investigated. Results demonstrated that Chit-IOCO significantly reduced the expression of TNF-α and COX-2, while Chit-TPP-IOCO reduced IL-6 in the LPS-stimulated macrophages RAW264.7. Cytotoxicity studies showed that the nano-cocktails inhibited the proliferation of macrophages. Additionally, Chit-IOCO exhibited higher in vitro MRI relaxivity than Chit-TPP-IOCO, indicating that Chit-IOCO is a better MRI contrast agent in macrophages. It was possible to track the delivery of Chit-IOCO to the inflamed livers of CCl₄-treated C57BL/6 mice, demonstrated by a shortened T₂^⁎ relaxation time of the livers after injecting Chit-IOCO into mice. In vivo anti-inflammatory and blood tests demonstrated that Chit-IOCO reduced inflammation-related proteins (TNF-a, iNOS and Cox-2) and bilirubin in CCl₄ treated C57BL/6. Histology images indicated that the nano-cocktails at the treatment doses did not affect the organs of the mice. Importantly, the nano-cocktail reduced fibrosis of CCl₄-treated mouse liver. This is the first reported data on the anti-inflammation and anti-fibrosis efficacy of Chit-IOCO in C57BL/6 mouse liver inflammation model. Overall, Chit-IOCO nanoparticles have shown great potential in MR imaging/detecting and treating/therapeutic capabilities for inflammatory diseases.

Simple Host-Guest Assembly for High-Resolution Magnetic Resonance Imaging of Microvasculature

Magnetic resonance angiography (MRA) is an important imaging technique that can be used to identify and characterize various types of vascular diseases. However, currently used molecular contrast agents are unsuitable for MRA due to the short intravascular retention time, the whole-body distribution, and the relatively low contrast effect. In this study, we developed a vascular analysis contrast agent (i.e., VasCA) for MRA, which is a simple and biocompatible 1:1 host-guest assembly of PEGylated β-cyclodextrin and gadolinium chelate with renal clearable size and high relaxivity (r1 = 9.27 mM-1 s-1). Its biocompatibility was confirmed by in vivo animal studies as well as in vitro 3D cell culture. In a tumor-bearing rat model, VasCA circulated in the blood vessels much longer (4.3-fold increase) than gadoterate meglumine (Dotarem) and was mainly excreted by the renal system after intravenous injection. This feature of VasCA allows characterization of tumor microvasculature (e.g., feeding and draining vessels) as well as visualization of small vessels in the brain and body organs. Furthermore, after treatment with an angiogenesis inhibitor (i.e., sorafenib), VasCA revealed the vessel normalization process and allowed the assessment of viable and necrotic tumor regions. Our study provides a useful tool for diverse MRA applications, including tumor characterization, early-stage evaluation of drug efficacy, and treatment planning, as well as diagnosis of cardiovascular diseases.

Superparamagnetic Iron Oxide Nanoparticles and Essential Oils: A New Tool for Biological Applications

Essential oils are complex mixtures of volatile compounds with diverse biological properties. Antimicrobial activity has been attributed to the essential oils as well as their capacity to prevent pathogenic microorganisms from forming biofilms. The search of compounds or methodologies with this capacity is of great importance due to the fact that the adherence of these pathogenic microorganisms to surfaces largely contributes to antibiotic resistance. Superparamagnetic iron oxide nanoparticles have been assayed for diverse biomedical applications due to their biocompatibility and low toxicity. Several methods have been developed in order to obtain functionalized magnetite nanoparticles with adequate size, shape, size distribution, surface, and magnetic properties for medical applications. Essential oils have been evaluated as modifiers of the surface magnetite nanoparticles for improving their stabilization but particularly to prevent the growth of microorganisms. This review aims to provide an overview on the current knowledge about the use of superparamagnetic iron oxide nanoparticles and essential oils on the prevention of microbial adherence and consequent biofilm formation with the goal of being applied on the surface of medical devices. Some limitations found in the studies are discussed.

Gold/alpha-lactalbumin nanoprobes for the imaging and treatment of breast cancer

Theranostic agents should ideally be renally cleared and biodegradable. Here, we report the synthesis, characterization and theranostic applications of fluorescent ultrasmall gold quantum clusters that are stabilized by the milk metalloprotein alpha-lactalbumin. We synthesized three types of these nanoprobes that together display fluorescence across the visible and near-infrared spectra when excited at a single wavelength through optical colour coding. In live tumour-bearing mice, the near-infrared nanoprobe generates contrast for fluorescence, X-ray computed tomography and magnetic resonance imaging, and exhibits long circulation times, low accumulation in the reticuloendothelial system, sustained tumour retention, insignificant toxicity and renal clearance. An intravenously administrated near-infrared nanoprobe with a large Stokes shift facilitated the detection and image-guided resection of breast tumours in vivo using a smartphone with modified optics. Moreover, the partially unfolded structure of alpha-lactalbumin in the nanoprobe helps with the formation of an anti-cancer lipoprotein complex with oleic acid that triggers the inhibition of the MAPK and PI3K-AKT pathways, immunogenic cell death and the recruitment of infiltrating macrophages. The biodegradability and safety profile of the nanoprobes make them suitable for the systemic detection and localized treatment of cancer.

Magnetic Nanoparticles in Cancer Therapy and Diagnosis

There is urgency for the development of nanomaterials that can meet emerging biomedical needs. Magnetic nanoparticles (MNPs) offer high magnetic moments and surface-area-to-volume ratios that make them attractive for hyperthermia therapy of cancer and targeted drug delivery. Additionally, they can function as contrast agents for magnetic resonance imaging (MRI) and can improve the sensitivity of biosensors and diagnostic tools. Recent advancements in nanotechnology have resulted in the realization of the next generation of MNPs suitable for these and other biomedical applications. This review discusses methods utilized for the fabrication and engineering of MNPs. Recent progress in the use of MNPs for hyperthermia therapy, controlling drug release, MRI, and biosensing is also critically reviewed. Finally, challenges in the field and potential opportunities for the use of MNPs toward improving their properties are discussed.

Biomimetic Gold Nanoshell-Loaded Macrophage for Photothermal Biomedicine

The purpose of this study was to investigate the effect of photothermal treatment (PTT) with gold nanoshell (ANS) using a macrophage-mediated delivery system in a head and neck squamous cell carcinoma (HNSCC) cell line. To achieve this, ANS-loaded rat macrophages (ANS-MAs) were prepared via the coculture method with ANS. The human HNSCC (FaDu cell) and macrophage (rat macrophage; NR8383 cell) hybrid spheroid models were generated by the centrifugation method to determine the possibility of using ANS-MAs as a cancer therapy. These ANS-MAs were set into the tumor and macrophage hybrid spheroid model to measure PTT efficacy. Kinetic analysis of the spheroid growth pattern revealed that this PTT process caused a decreasing pattern in the volume of the hybrid model containing ANS-MAs (p < 0.001). Comparison with empty macrophages showed harmony between ANS and laser irradiation for the generation of PTT. An annexin V/dead cell marker assay indicated that the PTT-treated hybrid model induced increasing apoptosis and dead cells. Further studies on the toxicity of ANS-MAs are needed to reveal whether it can be considered biocompatible. In summary, the ANS was prepared with a macrophage as the delivery method and protective carrier. The ANS was successfully localized to the macrophages, and their photoabsorption property was stationary. This strategy showed significant growth inhibition of the tumor and macrophage spheroid model under NIR laser irradiation. In vivo toxicology results suggest that ANS-MA is a promising candidate for a biocompatible strategy to overcome the limitations of fabricated nanomaterials. This ANS-MA delivery and PTT strategy may potentially lead to improvements in the quality of life of patients with HNSCC by providing a biocompatible, minimally invasive modality for cancer treatment.

Fate of GdF3 nanoparticles-loaded PEGylated carbon capsules inside mice model: a step toward clinical application

The successful translation of nanostructure-based bioimaging and/or drug delivery system needs extensive in vitro and in vivo studies on biocompatibility, biodistribution, clearance, and toxicity for its diagnostic applications. Herein, we have investigated the in vitro cyto-hemocompatibility, in vivo biodistribution, clearance, and toxicity in mice after systemic administration of GdF₃ nanoparticles loaded PEGylated mesoporous carbon capsule (GdF₃-PMCC)-based theranostic system. In vitro cyto-hemocompatibility study showed a very good biocompatibility up to concentration of 500 µg/ml. Biodistribution studies carried out from 1 h to 8 days showed that GdF₃-PMCC was found in major organs, such as liver, kidney, spleen, and muscle till 4th day and it was negligible in any tissue after 8th day. The clearance study was carried out for a period of 8 days and it was observed that the urinary system is the main route of excretion of GdF₃-PMCC. The tissue toxicity study was done for 15 days and histopathological analysis indicated that the GdF₃-PMCC based theranostic system does not have any adverse effect in tissues. Thus, PMCCs are nontoxic and can be applied as theranostic agents in contrast to the other carbon-based systems (PEGylated carbon nanotubes and PEGylated graphene oxide) which showed significant toxicity.

Dual-targeting and excretable ultrasmall SPIONs for T1-weighted positive MR imaging of intracranial glioblastoma cells by targeting the lipoprotein receptor-related protein

A multifunctional targeted nanoprobe composed of ultrasmall superparamagnetic iron oxide nanoparticles with surface-conjugated Angiopep-2 was successfully constructed for targeted MR imaging of intracranial glioblastoma.

E-jet 3D printed drug delivery implants to inhibit growth and metastasis of orthotopic breast cancer

Drug-loaded implants have attracted considerable attention in cancer treatment due to their precise delivery of drugs into cancer tissues. Contrary to injected drug delivery, the application of drug-loaded implants remains underutilized given the requirement for a surgical operation. Nevertheless, drug-loaded implants have several advantages, including a reduction in frequency of drug administration, minimal systemic toxicity, and increased delivery efficacy. Herein, we developed a new, precise, drug delivery device for orthotopic breast cancer therapy able to suppress breast tumor growth and reduce pulmonary metastasis using combination chemotherapy. Poly-lactic-co-glycolic acid scaffolds were fabricated by 3D printing to immobilize 5-fluorouracil and NVP-BEZ235. The implantable scaffolds significantly reduced the required drug dosages and ensured curative drug levels near tumor sites for prolonged period, while drug exposure to normal tissues was minimized. Moreover, long-term drug release was achieved, potentially allowing one-off implantation and, thus, a major reduction in the frequency of drug administration. This drug-loaded scaffold has great potential in anti-tumor treatment, possibly paving the way for precise, effective, and harmless cancer therapy.

Development of a Liposomal Formulation of Acetyltanshinone IIA for Breast Cancer Therapy

Acetyltanshinone IIA (ATA), synthesized in our group exhibiting good anti-breast cancer effects, is expected to replace the commonly used anti-ER+ breast cancer (breast cancer cells overexpressing the estrogen receptor) drug tamoxifen. To promote the clinical progress of ATA, polyethylene glycol (PEG)-modified liposomes were used to encapsulate ATA along with improving its bioavailability and in vivo anticancer efficiency. The resulting liposomal ATA exhibited a spherical shape with an average size of 188.5 nm. In vitro evaluations showed that liposomal ATA retained the anti-breast cancer efficacy of ATA while exerting much less cytotoxicity toward noncancerous cells. Significantly, pharmacokinetics analysis showed that the AUC0-24h of liposomal ATA was 59 times higher than that of free ATA, demonstrating increased bioavailability of ATA. Preclinical experiments demonstrated that liposomal ATA reduced the growth of ER-positive human breast tumor xenografts by 73% in nude mice, and the liposomal ATA exhibited a much lower level of toxicity than that of free ATA with respect to zebrafish larval mortality, body formation, and heart function during development. Moreover, 7-day and 21-day tissue toxicity levels were determined in mice by intravenous administration of a maximum dosage of liposomal ATA (120 mg/kg). The results showed no obvious tissue damage in major organs, including the heart, liver, spleen, kidney, and brain. In summary, we have developed a clinical formulation of liposomal ATA with the high bioavailability and potent efficacy for the treatment of ER-positive breast cancer.

Highly Catalytic Niobium Carbide (MXene) Promotes Hematopoietic Recovery after Radiation by Free Radical Scavenging

Ionizing radiation (IR) has been extensively used in industry and radiotherapy, but IR exposure from nuclear or radiological accidents often causes serious health effects in an exposed individual, and its application in radiotherapy inevitably brings undesirable damage to normal tissues. In this work, we have developed ultrathin two-dimensional (2D) niobium carbide (Nb₂C) MXene as a radioprotectant and explored its application in scavenging free radicals against IR. The 2D Nb₂C MXene features intriguing antioxidant properties in effectively eliminating hydrogen peroxide (H₂O₂), hydroxyl radicals (^•OH), and superoxide radicals (O₂^•-). Pretreatment with biocompatible polyvinylpyrrolidone (PVP)-functionalized Nb₂C nanosheets (Nb₂C-PVP NSs) significantly reduces IR-induced production of reactive oxygen species (ROS), resulting in enhanced cell viability in vitro. A single intravenous injection of Nb₂C-PVP significantly enhances the survival rate of 5 and 6.5 Gy irradiated mice to 100% and 81.25%, respectively, and significantly increases bone marrow mononuclear cells after IR. Critically, Nb₂C-PVP reverses the damage of the hematopoietic system in irradiated mice. Single administration of Nb₂C-PVP significantly increases superoxide dismutase (SOD) activities, decreases malondialdehyde levels, and thereby reduces IR-induced pathological damage in the testis, small intestine, lung, and liver of 5 Gy irradiated mice. Importantly, Nb₂C-PVP is almost completely eliminated from the mouse body on day 14 post treatment, and no obvious toxicities are observed during the 30-day post treatment period. Our study pioneers the application of 2D MXenes with intrinsic radioprotective nature in vivo.

Hydrophobic Polyampholytes and Nonfreezing Cold Temperature Stimulate Internalization of Au Nanoparticles to Zwitterionic Liposomes

Nanomedicine relies on the effective internalization of nanoparticles combined with polymeric nanocarriers into living cells. Thus, exploration of internalization is essential for improving the efficacy of nanoparticle-based strategies in clinical practice. Here, we investigated the physicochemical internalization of gold nanoparticles (AuNPs) conjugated with hydrophobic polyampholytes into cell-sized liposomes at a low but nonfrozen temperature. The hydrophobic polyampholytes localized in the disordered phase of the membrane, and internalization of AuNPs was enhanced in the presence of hydrophobic polyampholytes together with incubation at -3 °C as compared to 25 °C. These results contribute toward a mechanistic understanding for developing a model nanomaterials-driven delivery system based on hydrophobic polyampholytes and low temperature.

Impact of Surface-Engineered ZnO Nanoparticles on Protein Corona Configuration and Their Interactions With Biological System

In biological system, the interaction between nanoparticles (NPs) and serum biomolecules results in the formation of a dynamic corona of different affinities. The formed corona enriched with opsonin protein is recognized by macrophages and immune effector cells, resulting in rapid clearance with induced toxicity. Hence, to reduce corona genesis, surface-engineered ZnO (c-ZnO) NPs were in situ synthesized using a polyacrylamide-grafted guar gum (PAm-g-GG) polymer that provided surface neutrality to the NPs. Furthermore, we studied the characteristics of the corona formed onto uncapped anionic ZnO (bared ZnO [b-ZnO]) NPs and c-ZnO NPs by serum incubation. The result shows that b-ZnO NPs were wrapped with a high amount of serum proteins, particularly opsonin (IgG and complement), compared with c-ZnO NPs. These corona findings helped us substantially in interpretation of in vivo biokinetics studies. The in vivo study was accomplished by oral administration of NPs to Swiss mice at doses of 300 and 2000 mg/kg body weight. The studies performed on the cellular uptake, intracellular particle distribution, cytotoxicity, and pharmacokinetics of NPs indicated that b-ZnO NPs experienced higher immune cell recognition, hepatic inflammation, and resultant rapid clearance from the system, unlike c-ZnO NPs. Thus, capping of NPs by a neutral polymer has provided limited binding sites for undesired proteins around NPs, which limits immune system activation.

Magnetic hyperthermia therapy for the treatment of glioblastoma: a review of the therapy's history, efficacy and application in humans

Hyperthermia therapy (HT) is the exposure of a region of the body to elevated temperatures to achieve a therapeutic effect. HT anticancer properties and its potential as a cancer treatment have been studied for decades. Techniques used to achieve a localised hyperthermic effect include radiofrequency, ultrasound, microwave, laser and magnetic nanoparticles (MNPs). The use of MNPs for therapeutic hyperthermia generation is known as magnetic hyperthermia therapy (MHT) and was first attempted as a cancer therapy in 1957. However, despite more recent advancements, MHT has still not become part of the standard of care for cancer treatment. Certain challenges, such as accurate thermometry within the tumour mass and precise tumour heating, preclude its widespread application as a treatment modality for cancer. MHT is especially attractive for the treatment of glioblastoma (GBM), the most common and aggressive primary brain cancer in adults, which has no cure. In this review, the application of MHT as a therapeutic modality for GBM will be discussed. Its therapeutic efficacy, technical details, and major experimental and clinical findings will be reviewed and analysed. Finally, current limitations, areas of improvement, and future directions will be discussed in depth.

Iron oxide nanoparticles for targeted imaging of liver tumors with ultralow hepatotoxicity

Even though iron oxide (Fe₃O₄) nanoparticles are promising materials for magnetic resonance imaging (MRI) contrast agents, their biocompatibility and targeting efficacy still need to be improved. Herein, we modified glycyrrhetinic acid (GA) groups on Fe₃O₄ nanoparticles (Fe₃O₄@cGlu-GA) for liver tumor-targeted imaging. To evaluate the biocompatibility of these nanoparticles, we studied their cytotoxicity, hemolysis, and hepatotoxicity. We measured the uptake of Fe₃O₄@cGlu-GA nanoparticles in normal and liver tumor cells, then we investigated the specificity of Fe₃O₄@cGlu-GA nanoparticles in mouse models bearing subcutaneous and orthotopic liver tumors. With good biocompatibility and targeting efficacy both in vitro and in vivo, the Fe₃O₄@cGlu-GA nanoparticles are promising MRI contrast agents with ultralow hepatotoxicity and show great improvement on existing Fe₃O₄-based nanoparticles.

Tumor-targeted and nitric oxide-generated nanogels of keratin and hyaluronan for enhanced cancer therapy

The development of safe and effective nano-drug delivery systems to deliver anticancer drugs to targeted cells and organs is crucial to enhance the therapeutic efficacy and overcome unwanted side effects of chemotherapy. Herein, we prepared CD44-targeted dual-stimuli responsive human hair keratin and hyaluronic acid nanogels (KHA-NGs) through a simple crosslinking method. KHA-NGs, which consisted of spheres 50 nm in diameter, were used as carriers to load the anticancer drug doxorubicin hydrochloride (DOX). The drug release, cellular uptake, cytotoxicity, and targeting ability of DOX-loaded KHA-NGs (DOX@KHA-NGs) were assessed in vitro and the anticancer effects were further evaluated in vivo. The DOX@KHA-NGs had a super-high drug loading capacity (54.1%, w/w) and were stable under physiological conditions (10 μM glutathione (GSH)), with the drug being rapidly released under a tumor cell microenvironment of trypsin and 10 mM GSH. Cellular uptake and in vitro cytotoxicity results indicated that DOX@KHA-NGs specifically targeted cancer cells and effectively inhibited their growth. Furthermore, KHA-NGs were capable of improving intracellular nitric oxide levels, which sensitizes the cells and enhances the anticancer efficacy of chemotherapeutic drugs. In vivo experiments showed that DOX@KHA-NGs had a better anti-tumor effect and lower side effects compared to free DOX. These results suggest that the bio-responsive KHA-NGs have potential applications for targeted cancer therapy.

Superfine Magnetic Resonance Imaging of the Cerebrovasculature Using Self-Assembled Branched Polyethylene Glycol-Gd Contrast Agent

Magnetic resonance angiography is an attractive method for the visualization of the cerebrovasculature, but small-sized vessels are hard to visualize with the current clinically approved agents. In this study, a polymeric contrast agent for the superfine imaging of the cerebrovasculature is presented. Eight-arm polyethylene glycol with a molecular weight of ≈17 000 Da conjugated with a Gd chelate and fluorescein (F-8-arm PEG-Gd) is used. The relaxivity rate is 9.3 × 10^-3 m^-1 s^-1 , which is threefold higher than that of free Gd chelate. Light scattering analysis reveals that F-8-arm PEG-Gd is formed by self-assembly. When the F-8-arm PEG-Gd is intravenously injected, cerebrovasculature as small as 100 µm in diameter is clearly visualized. However, signals are not enhanced when Gd chelate and Gd chelate-conjugated 8-arm PEG are injected. Furthermore, small vasculature around infarct region in rat stroke model can be visualized. These results suggest that F-8-arm PEG-Gd enhances the MR imaging of cerebrovasculature.

Development and Characterization of Magnetite/Poly(butylcyanoacrylate) Nanoparticles for Magnetic Targeted Delivery of Cancer Drugs

A great attention is presently paid to the design of drug delivery vehicles based on surface-modified magnetic nanoparticles. They can, in principle, be directed to a desired target area for releasing their drug payload, a process triggered by pH, temperature, radiation, or even magnetic field. To this, the possibility of forming part of diagnostic tools by enhanced magnetic resonance imaging or that of further treatment by magnetic hyperthermia can be added. Bare particles are rapidly eliminated from the bloodstream by the phagocyte mononuclear system, leading to short biological half-life. It is hence required to coat them in order to increase their biocompatibility and facilitate the drug incorporation. In this work, magnetite nanoparticles were coated with poly(butylcyanoacrylate) (PBCA) manufactured and characterized with regard to their physical properties and their suitability as a platform for magnetically controlled drug delivery. The average diameter of magnetite and core-shell nanoparticles was 97 ± 19 and 140 ± 20 nm, respectively. Infrared analysis, electrophoretic mobility, surface thermodynamics analysis, and X-ray diffraction all confirmed that the magnetic particles were sufficiently covered by the polymer in the composite nanoparticles. In addition, assays using normal (CCD-18 and MCF-10A) and tumoral (T-84 and MCF-7) cell lines derived from colon and breast tissue, respectively, demonstrated that nanocomposites have low or negligible cytotoxicity. It is concluded that PBCA-coated magnetite core-shell nanoparticles represent a remarkable promise as a platform for magnetically controlled drug delivery.

Use of Ultrasmall Superparamagnetic Iron Oxide Enhanced Susceptibility Weighted Imaging and Mean Vessel Density Imaging to Monitor Antiangiogenic Effects of Sorafenib on Experimental Hepatocellular Carcinoma

We investigated effectiveness of ultrasmall superparamagnetic iron oxide enhanced susceptibility weighted imaging (USPIO-enhanced SWI) and mean vessel density imaging (Q) in monitoring antiangiogenic effects of Sorafenib on orthotopic hepatocellular carcinoma (HCC). Thirty-five HCC xenografts were established. USPIO-enhanced SWI and Q were performed on a 1.5 T MR scanner at baseline, 7, 14, and 21 days after Sorafenib treatment. Intratumoral susceptibility signal intensity (ITSS) and Q were serially measured and compared between the treated (n = 15) and control groups (n = 15). Both ITSS and Q were significantly lower in the treated group at each time point (P < 0.05). Measurements in the treated group showed that ITSS persisted at 7 days (P = 0.669) and increased at 14 and 21 days (P < 0.05), while Q significantly declined at 7 days (P = 0.028) and gradually increased at 14 and 21 days. In the treated group, significant correlation was found between Q and histologic microvessel density (MVD) (r = 0.753, P < 0.001), and ITSS correlated well with MVD (r = 0.742, P = 0.002) after excluding the data from baseline. This study demonstrated that USPIO-enhanced SWI and Q could provide novel biomarkers for evaluating antiangiogenic effects of Sorafenib on HCC.

Tracking short-term biodistribution and long-term clearance of SPIO tracers in magnetic particle imaging

Magnetic particle imaging (MPI) is an emerging tracer-based medical imaging modality that images non-radioactive, kidney-safe superparamagnetic iron oxide (SPIO) tracers. MPI offers quantitative, high-contrast and high-SNR images, so MPI has exceptional promise for applications such as cell tracking, angiography, brain perfusion, cancer detection, traumatic brain injury and pulmonary imaging. In assessing MPI's utility for applications mentioned above, it is important to be able to assess tracer short-term biodistribution as well as long-term clearance from the body. Here, we describe the biodistribution and clearance for two commonly used tracers in MPI: Ferucarbotran (Meito Sangyo Co., Japan) and LS-oo8 (LodeSpin Labs, Seattle, WA). We successfully demonstrate that 3D MPI is able to quantitatively assess short-term biodistribution, as well as long-term tracking and clearance of these tracers in vivo.

Preparation, characterization, biotoxicity, and biodistribution of thermo-responsive magnetic complex micelles formed by Mn0.6Zn0.4Fe2O4 and a PCL/PEG analogue copolymer for controlled drug delivery

A thermo-responsive PCL/PEG analogue copolymer (PCL-[b-P(MEO₂MA-co-OEGMA)]₂) with a lower critical solution temperature (LCST) of 40.4 °C at an MEO₂MA/OEGMA molar ratio of 87 : 13 was designed and synthesized. The copolymer was subsequently labeled by coupling with fluorescein isothiocyanate (FITC). Thermo-responsive magnetic PCL-[b-P(MEO₂MA-co-OEGMA)]₂/Mn_0.6Zn_0.4Fe₂O₄ (MZF) complex micelles were prepared by a self-assembly method. Doxorubicin (DOX) was loaded into the magnetic complex micelles as a model drug, and the DOX-MZF-micelles showed well-controlled thermo-responsive release both at externally fixed temperatures and in the presence of an alternating magnetic field (AMF). Both the blank polymer micelles and the magnetic complex micelles exhibited excellent stability in normal saline and serum. Based on the detection of the FITC fluorescence signal, the micelles were found to be effectively labeled by FITC. Furthermore, the biological toxicity of micelles was studied in vitro and in vivo. In vitro toxicity studies to evaluate cell viability and cell toxicity were performed by employing WST-1 and LDH release assays using HL7702 cells, respectively. In vivo biotoxicity studies were conducted in ICR mice through a series of tests: general conditions, body weight shifts, serum biochemistry profiles, and organ coefficient tests. All the biological toxicity results obtained from the blank polymer micelles and the magnetic complex micelles indicated their good biocompatibility and nontoxicity. The in vivo biodistribution studies of the FITC-labeled magnetic complex micelles were performed in the ICR mice. The copolymer was cleared by the kidney and spleen, while the MZF nanoparticles were cleared by the liver in time, causing no adverse effects on organisms. The thermo-responsive magnetic complex micelles were shown to be an ideal nanocarrier for anticancer drug delivery in terms of controlled release, stability, biocompatibility and safety.

Recent Advances on Inorganic Nanoparticle-Based Cancer Therapeutic Agents

Inorganic nanoparticles have been widely investigated as therapeutic agents for cancer treatments in biomedical fields due to their unique physical/chemical properties, versatile synthetic strategies, easy surface functionalization and excellent biocompatibility. This review focuses on the discussion of several types of inorganic nanoparticle-based cancer therapeutic agents, including gold nanoparticles, magnetic nanoparticles, upconversion nanoparticles and mesoporous silica nanoparticles. Several cancer therapy techniques are briefly introduced at the beginning. Emphasis is placed on how these inorganic nanoparticles can provide enhanced therapeutic efficacy in cancer treatment through site-specific accumulation, targeted drug delivery and stimulated drug release, with elaborations on several examples to highlight the respective strategies adopted. Finally, a brief summary and future challenges are included.

The use of magnetic nanoparticles in cancer theranostics: Toward handheld diagnostic devices

Magnetic nanoparticles are frequently used in a wide range of biomedical applications. In the first part of this review the most commonly used preparation and surface coating approaches of MNPs are briefly summarized including multifunctional hybrid particles. The second part gives a detailed overview of the use of MNPs in "traditional" biomedical applications related to cancer theranostics, like magnetic resonance imaging, drug delivery, hyperthermia and also their applicability in the next generation of point of care devices based on micro nuclear magnetic resonance and surface enhanced Raman spectroscopic detection technology that all can be routinely applied in everyday clinical practice.

Contrast-enhanced susceptibility weighted imaging with ultrasmall superparamagnetic iron oxide improves the detection of tumor vascularity in a hepatocellular carcinoma nude mouse model

PURPOSE

To evaluate the effectiveness of contrast-enhanced susceptibility-weighted imaging with ultrasmall superparamagnetic iron oxide (USPIO-enhanced SWI) in the assessment of intratumoral vascularity in hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

Orthotopic xenograft HCC nude mouse models were established first and magnetic resonance imaging (MRI) examinations were performed on a 1.5T MR scanner 28 days later. Three groups of mice, 10 in each, were imaged using unenhanced and USPIO-enhanced SWI at doses of 4, 8, and 12 mg Fe/kg. Intratumoral susceptibility signal intensity (ITSS) was scored. ITSS-to-tumor contrast-to-noise ratio (ITSST-CNR) was measured. These measurements were compared between unenhanced and USPIO-enhanced SWI at each dose and differences in the measurements between different dose groups were estimated. Correlation between ITSS and tumor microvessel density (MVD) was analyzed.

RESULTS

Compared with unenhanced SWI, significantly higher ITSS was identified on USPIO-enhanced SWI at doses of 8 mg Fe/kg (Z = -2.000, P = 0.046) and 12 mg Fe/kg (Z = -2.333, P = 0.020). Significantly higher ITSST-CNR was found on USPIO-enhanced SWI than that on unenhanced SWI (P < 0.05). Significantly higher ITSST-CNR at a dose of 8 mg Fe/kg was observed than that at 4 mg Fe/kg (Z = -3.326, P = 0.001). Positive correlation between ITSS on USPIO-enhanced SWI at a dose of 8 mg Fe/kg and tumor MVD was demonstrated (r = 0.817, P = 0.004).

CONCLUSION

USPIO-enhanced SWI at a dose of 8 mg Fe/kg greatly improves the detection of intratumoral vascularity in a xenograft HCC model. J. Magn. Reson. Imaging 2016;44:288-295.

Ultra-large-scale production of ultrasmall superparamagnetic iron oxide nanoparticles for T1-weighted MRI

Ultra-large-scale production of ultrasmall superparamagnetic iron oxide nanoparticles for magnetic resonance angiography.

Eryptosis Indices as a Novel Predictive Parameter for Biocompatibility of Fe3O4 Magnetic Nanoparticles on Erythrocytes

Fe3O4 magnetic nanoparticles (Fe3O4-MNPs) have been widely used in clinical diagnosis. Hemocompatibility of the nanoparticles is usually evaluated by hemolysis. However, hemolysis assessment does not measure the dysfunctional erythrocytes with pathological changes on the unbroken cellular membrane. The aim of this study is to evaluate the use of suicidal death of erythrocytes (i.e. eryptosis indices) as a novel predictive and prognostic parameter, and to determine the impact of Fe3O4-MNPs on cellular membrane structure and the rheology properties of blood in circulation. Our results showed that phosphatidylserine externalization assessment was significantly more sensitive than classical hemolysis testing in evaluating hemocompatibility. Although no remarkable changes of histopathology, hematology and serum biochemistry indices were observed in vivo, Fe3O4-MNPs significantly affected hemorheology indices including erythrocyte deformation index, erythrocyte rigidity index, red blood cell aggregation index, and erythrocyte electrophoresis time, which are related to the mechanical properties of the erythrocytes. Oxidative stress induced calcium influx played a critical role in the eryptotic activity of Fe3O4-MNPs. This study demonstrated that Fe3O4-MNPs cause eryptosis and changes in flow properties of blood, suggesting that phosphatidylserine externalization can serve as a predictive parameter for hemocompatibility assay.